Comentarii la: Scalarea iahturilor AC este mai ciudat decât crezi

De: Adrian Thompson

Adrian Thompson — Thu, 02 Feb 2023 16:41:17 +0000

Similitude or scale effect normally works against you as you increase in boat size. For example if you were scaling a catamaran of 10m which weighed 1000kg and had 100m sqm of sail area, to one of twice the actual size, you would end up with a 20m boat weighing 8000 kg with 400msq of sail area. The sail area to displacement ratio tumbles by half. This assumes the same structural stiffness is retained in the larger version. In reality bigger structures end up floppier or less stiff and less robust, which can lead to structural fragility – been there!

De: Clive Engel

Clive Engel — Thu, 02 Feb 2023 06:26:14 +0000

Two NZ AC-40’s on the water in Auckland – Two Boat testing could he vital!

De: saga mauga

saga mauga — Thu, 02 Feb 2023 06:06:43 +0000

It's strange that No one has mentioned the hull shape on Luna Rosa similar to Te Rehutai

De: Jeff Condell

Jeff Condell — Wed, 01 Feb 2023 12:19:03 +0000

The lengths that you go to for the cause

De: Astons Sailing History

Astons Sailing History — Wed, 01 Feb 2023 09:36:17 +0000

I Ave grave concerns around INEOS and the path the are going down.

De: Alan Merry

Alan Merry — Tue, 31 Jan 2023 06:16:19 +0000

A great video highlighting the complexities involved in scaling boats. I suspect that the AC40 ETNZ platform is actually the most useful for development purposes given that it has a fixed set of variables, only those that are modifiable in the full size AC75. It is also probable that boat and hull design will play a much smaller part in the AC37 compared with sail control and boat handling thereby reducing the need to exactly scale these development boats.

De: Peter Ebel

Peter Ebel — Mon, 30 Jan 2023 16:40:28 +0000

A former model sailor here, engineer and successful participant in a WC, sailing experience from dinghies to tall ships, monos, cats and fast trimarans.

You can't scale sailing boats, simple as it is!
- speed across the water surface is to be scaled with the square root of the scaling factor
- weights are to be scaled in the cubic
- areas (forces in sails and foils) are to be scaled in the square
- Reynolds are in linear scaling
- wind vs boat speed is different
- the wind gradient with the distance of the water surface is different
.....

So with every scale the balance of forces, ... is different resulting in differences in concept, performance and handling.
A factor two in length does make a significant difference in the real world
But you can validate your simulation models, design concepts, algorithms, ...
But you have to keep in mind: the more data you get out of successful sailing, the better it is. I do see the Kiwi team and America on a good path of preparation - with a very different approach.

De: Mike H

Mike H — Mon, 30 Jan 2023 12:22:32 +0000

My brain fell out about 4.10 in

De: Solo sailing team

Solo sailing team — Sun, 29 Jan 2023 15:09:01 +0000

What is your favorite team?

De: ya33a

ya33a — Sun, 29 Jan 2023 11:16:10 +0000

Remember when you reduce something in 'area' it's 'squared', like sails, appear 'flat' but a 3 dimensional object is 'Cubed' when enlarged or reduced, plus the density of air is exactly the same at any scale and water density is the same, so… that's only part of the issue…